The present invention relates to a novel erythropoietin product originating in the urine of healthy human and a method for the preparation thereof. More particularly, the invention relates to a novel method for the purification of the crude erythropoietin obtained from the urine of healthy human by a specific procedure to give a novel erythropoietin product exhibiting no inhibiting activity against erythropoiesis and the erythropoietin product thus prepared.
Erythropoietin is, as is well known, a hormone having an activity to stimulate erythropoiesis in a specific manner which is an indispensable factor for the differentiation of the blood stem cells into red blood corpuscles so that deficiency or decreased concentration thereof in blood causes anemia.
Therefore, erythropoietin is a promising therapeutic medicine in the clinic treatment of anemia or, in particular, renal anemia. Unfortunately, the use of erythropoietin is not so prevailing in the practical therapy due to the low availability thereof.
The hitherto undertaken method for the preparation of erythropoietin products is almost exclusively the concentration and purification of the urine of the patients of high erythropoietin secretion suffering from aplastic anemia and the like diseases. Because of the limited supply of such patient urine as an obstacle to the practical use of erythropoietin, it is highly desirable to prepare erythropoietin products from the urine of healthy human available in large volumes. A problem in the use of the urine of healthy human is the low content of erythropoietin therein in comparison with the patient urine. In addition, the urine of healthy human contains certain inhibiting factor against erythropoiesis in a considerably high concentration so that no satisfactory therapeutic effect would be obtained even if the erythropoietin product prepared from the urine of healthy human be administered to a patient of anemia.
The inventors have previously proposed a successful method for the preparation of an erythropoietin product from the urine of healthy human (see U.S. Pat. No. 4,303,650) but the erythropoietin product prepared by the proposed method still has the above mentioned problem of the inhibition against erythropoiesis and was not sufficient to satisfy the therapeutic requirement for anemia.